Fernando A. Martínez Torres was a 2009 and 2010 RESESS intern. He was a star recruiter of new RESESS interns for the summer of 2010 in his home department at the University of Puerto Rico, Mayaguez. Fernando plans to attend graduate school in the field of geophysics. Fernando loves to travel and see new places, and has an upbeat outlook on life. He got the prize for visiting the most National Parks in one summer as a RESESS intern.
2009- Geochemical evidence for flat-slab subduction in Cenozoic western North America
The process of gully erosion is not completely understood by geologists due to insufficient data. We use various techniques including 3-D laser scanning (terrestrial and airborne), real-time kinematic-GPS and aerial photography to acquire new data from a study site at Bijou Creek, Colorado, to help improve our understanding of this process. Analysis of the data shows that the average rate of erosion in the head cut of this specific gully is 0.5 meters per year with the rate of movement every year to be generally very constant. We also analyzed the rate of erosion of other gullies in Bijou Creek and found that their rates of erosion vary depending on the location of the landscape. The aerial photographs confirm the rate of erosion for the general head cut of the gully, but with TLS, we can analyze the locations of the gully being eroded the quickest and how much each area has been eroded. By comparing TLS scans from 2008 and 2009, we observed that the main erosion is in the head cut of the gully; everything else in the scan area was seen to move at a slower rate (or showed no movement over the this period).
Full color point cloud image printed in the 2009 Earth, Wind, Sea, and Sky. The colors show the difference in meters from 2008 to 2009.
2010- Improving Slab 1.0 subduction zone models using regional constraints from the Eastern Pacific
Knowledge of the geometry of subduction zones is essential for understanding the rupture processes of great (magnitude > 8) earthquakes, and is a key constraint for many other modeling efforts, including the study of subduction zone mechanics and interpretation of seismic structure and mantle geodynamics. Inferences of plate geometry are usually made based on seismicity; the hypocenters of subduction zone earthquakes tell us the locations of their fault rupture planes—our best estimate of the location of the slab—so it is important to obtain well-resolved hypocentral locations. In this study, we work with Slab1.0, a global three-dimensional model of subduction zone geometries. These models are compiled primarily using teleseismic data, which can often be less accurate than regional data because they use global observations rather than using local seismic networks. In this study, we compare Slab1.0 models with models compiled from regional studies, digitized from geo-science literature. After digitization, these models can be quantitatively compared to Slab1.0 models covering the same region, generating difference maps of their vertical offset. We also analyze the methodology and data sets used by each study to verify the accuracy of the regional models. By quantifying the differences between models and by assessing the reasons for those differences we can identify areas where Slab1.0 can be improved.